The second chapter of the thesis was devoted to ‘Case study: Dreissena polymorpha in the Bulgarian inland water bodies - population structure and relation to environmental parameters’. The main aims of this study were:

(1) the analysis of the population structure in different sites in Bulgaria, in order to evaluate the establishment status of the translocated species D. polymorpha in terms of population density and reproductive capability; and

(2) the identification of environmental variables characterising invaded sites and, within these invaded sites, environmental conditions determining the achievement of high population densities.